Tonsillotome



Feb. 4, 194-1. J, T, MOOR I 2,230,431

TONSILLOTOME Filed July 10, 1957 51.5 1 1.1 F1- .5 F .5 5 j j 5 mmmPatented Feb. 4, 1941 UNITED STATES PATENT OFFICE 4 claims.

This invention relates to instrument of the surgical snare type whichare specially adapted for removing tonsils. It is in the nature of animprovement on the instrument which forms the subject matter ofapplication Serial No. 127,705,

filed Feb. 25, 1937.

The primary object of the invention is to provide a lever arrangementwhich will be brought into operation only at the time at which theresistance of the tissues to crushing and cutting becomes sufficient tomake a direct pull by the fingers difficult.

A further object is to provide a construction having a small number ofparts which are readily taken apart for cleaning and sterilization andwhich are easily assembled for use.

In the drawing representing a preferred embodiment of the invention,Figure 1 is a top plan view of the entire device assembled ready for useand with a tonsil hook lying within the loop of the snare; Fig. 2 is abottom-plan view of the device with the levers in the position to exerttheir greatest force with the hook removed and with the outer end of thesnare close to the counterpressure bar; Fig. 3 is a top plan view of thecounterpressure bar; Fig. 4 is a top plan view of the snare bar with thelevers pivoted thereon; Fig. 5 is a plan view of the snare; Fig. 6 is abottom-plan of the retention clip; Fig. 7 is an elevation of the screwwhich connects the snare bar with the retention clip; Fig. 8 is asection through the guideway on the line 8-8 of Fig. 2, and Fig. 9 is aside elevation of the device as seen from the left in Fig. 1.

A counterpressure bar I has a thumb loop 2 at one end and an expandedguide portion 3 at the other end comprising two flat perforated plates 4and 5 connected at each side as at 6, to form a guideway therebetweenfor a fiat snare 1 of the form shown in Fig. 5. The snare will be madeof stainless steel or of any other suitable material having thenecessary strength, resiliency, durability and capacity for being easilysterilized.

The broad front end of the snare is perforated to form a loop having anarrow rim portion 8 at its forward end, and near its rear end, it has aslot 9 to receive a lug Ill at the front end of the snare bar II. Thelug ID has a notch l2 at its front end to receive the portion of thesnare at the front end of the slot 9, the notch being deep enough topermit rearward movement of the snare to a point at which the rear endof the slot 9 can clear the rear end of the lug 10. The flexible rearend of the snare can then be pressed down and slid forward to bring therear end of the slot 9 into a notch IS in the rear end of the lug II],this forward movement being sufficient to carry a V-shaped notch M inthe rear end of the snare to the front end of a V-shaped elevation I5 onthe snare bar. The rear notch I3 is 5 not as deep as the front notch l2and the snare thus cannot slide forward enough to disengage from the lugat its forward end, but the resilient rear end will bend down inengagement with the sides of the elevation l5 which will thus prevent l0rearward movement of the snare out of the slot or notch l3 as well asprevent sidewise movement of the end of the snare on the snare bar. Thisform of engagement is the same as that shown in the previous applicationmentioned above. 15

The counterpressure bar I has two longitudinal slots l6 and i1 and thesnare bar has a relatively short slot I 8 which in the assembledposition of the device lies opposite the slot IS. A retention clip l9has a T-shaped lug 20 which can be passed 20 through the slots 1-6 andI8 when the clip lies at right angles to the snare bar andcounterpressure I bar, and when the clip is then rotated a quarter turn,the ends of the lug will extend on both sides of the slot l8 as shown inFig. 2. The screw 25 21 is then passed through an opening 22 in the clipI9 and through the slot I1, to enter a threaded opening 23 in thesnarebar.

It will be evident that the lug 20 and the screw 2| can slidelongitudinally of the slots 16 and I1 30 2 respectively, one end ofeither slot acting to limit the forward and rearward sliding movement ofthe snare bar on the counterpressure bar. The clip i9 is preferablyresilient and bent enough to exert pressure on the two bars to holdthemv to- 35 gether while permitting easy sliding.

A pair of lugs 24 project from opposite sides of the snare bar ll eachlug having a lever 25 pivoted thereto and a finger loop 26 is formed in.each lever for easy engagement by the fingers of 40 the same hand ofwhich the thumb engages the loop 2 of the bar I.

When assembled, the finger loop ends of the levers are at the forwardend, as shown in Fig. '1 in the full line position, with the inner sidesof 45 the loops closely adjacent to the straight sides of thecounterpressure bar and with the sides 21 of the opposite ends of thelevers also closely in contact with the sides of the bar I below thepivots of the levers. The snare bar can slide freely on 50 the bar Ifrom the full line position to the broken line position of the levers inFig. 1, but the levers cannot swing outward on their pivots because ofthe engagement of the lower ends of the levers against the sides of thebar I. 55

The counterpressure bar has a pair of lugs 28 projecting from oppositesides between the slots, and as the levers slide to the broken lineposition, their ends engage with the lugs. On each side of the bar I andon each side of the lugs, recesses 29 are formed of sufiicient depth topermit the lower ends of the levers to swing inward. In the end of eachlever 25, a notch 30 is formed of a depth such that the levers can swingaround their pivots with the ends of the lugs 28 entering into therecesses 30 as indicated in Fig. 2 in full line position.

In Fig. 1, the snare is shown in full lines as extending outward beyondthe end of the guide portion 3 to a point at which substantially thewhole loop is available to receive a tonsil. In the broken lineposition, the loop has slid about the length of half of the opening, andas the levers swing outward to the full line position of Fig. 2, theloop enters the guideway passage in the end of the bar l until only anarrow opening is left. This is the position in which the tissues offerthe greatest resistance to further movement of the loop. They have beencrushed and compressed in bringing them to this point, but considerableforce is still required to complete the severance. The levers, inengagement with the lugs 28 and extending at substantially right anglesto the bar I afiord a leverage of about three to one, and as they movefrom the full line position to the broken line position, the loop ispulled entirely into the guideway.

It will be seen that during the first part of the movement of the snareinto the guideway passage, the action of the loop is a direct pull ofthe rim portion 8 against the relatively blunt front edge of thecounterpressure bar, resulting in a crushing action, but as the loopreaches the position shown in full lines in Fig. 2, the edge of the loopmoves transversely of the curved front edge of the guide plates 4 and 5to give a shearing action to sever the fibers of the anterior pillarafter the tonsil tissue has been crushed.

The tonsil hook 3I' has a handle portion 32 to engage the sides of thebar I and the notches 33 near the thumb loop act to prevent longitudinalsliding movement of the handle as the hook and tonsillotome are graspedin the hand of the operator with the hook through the loop as shown inFig. 1. The tonsilengaged by the hook is dissected loose in the usualway from the anterior pillar, the snare is then slid off the hook aroundthe tonsil and the loop is drawn into its guideway by sliding the snarebar along the counterpressure bar I until thelever ends engage the lugs28. A continued pull on the levers 25 will rotate them outward on theirpivots to move the loop the short remaining distance into its guideway,shearing off thelast remaining fibers smoothly and cleanly.

While the design shown in the drawing has proved efficient in actualuse, it will be evident that many changes in size, form, and proportionof parts and in the details of construction may be made withoutdeparting from the invention as claimed.

I claim:

1. A surgical instrument comprising a com-- terpressure bar having aguideway formed therein, a snare bar slidably mounted upon thecounterpressure bar and having a snare thereon projecting through saidguideway, levers pivoted on opposite sides of the snare bar andengageable at their inner ends with opposite sides of thecounterpressure bar to force it longitudinally of the snare bar as thesnare is drawn into the said guideway.

2. A surgical instrument comprising a counterpressure bar having aguideway formed therein, a snare bar slidably mounted upon thecounterpressure bar and having a snare thereon projecting through saidguideway, levers pivoted upon opposite sides of said snare bar, a lugprojecting from each side of the counterpressure bar for engagement withthe end of the lever on the corresponding side of the snare bar wherebyto force the counterpressure bar longitudinally of the snare bar as thelever is swung on its pivot.

3. A surgical instrument comprising a counterpressure bar having aguideway formed therein, a snare slidable within the said guideway, asnare bar to which the snare is detachably connected, the snare barbeing slidably connected with the counterpressure bar, and leverspivotally connected with opposite sides of the snare bar and havingtheir end portions in slidable engagement with the counterpressure barfrom a position in which the snare projects outward from the guideway toa position in which the snare is partially withdrawn into the guideway,the counterpressure bar having recess at points opposite. the ends ofthe levers at the inner end of their sliding movement on thecounterpressure bar, the recesses permitting a swinging movement of thelevers outward on their pivot with the ends of the levers in engagementwith the counterpressure bar to cause further relative movement of thesnare bar and the counterpressure bar sufficient to withdraw the snareentirely within the guideway.

4. A surgical instrument comprising a counterpressure bar having aguideway formed therein, a snare slidable within the guideway, a snarebar to which the snare is secured, the snare bar being slidablyconnected with the counterpressure bar and having lugs on opposite sidesthereof, levers pivotally connected with the lugs and having their endportions in slidable engagement with opposite sides of thecounterpressure bar from a position in which the snare projects outwardfrom the guideway to a position in which the snare is partiallywithdrawn into the guideway, the counterpressure bar being formed withlugs engageable by the ends of the levers at the end of their slidingmovement and being formed with recesses adjacent to said lugs to permitinward movement of the inner ends of the levers as their outer endsswing outward, the inner ends of the levers being formed to engagethe-lugson the counterpressure bar whereby to force the counterpressurebar longitudinally of the snare bar as the levers swing outward aroundtheir pivots.

JOHN TERRELL MOORE.

